I am trying to swap out an incandescent light for an LED light on my electric scooter. I've managed to remove the old incandescent light (right in figure) from its holster. When I replace it with the LED (left) light that I recently purchased, the LED doesn't light up, while the incandescent light does. The holster is designed such that the bulbs can be inserted in one direction only.

The incandescent light is rated at 12V, while the LED says from 9-84V if I'm not reading it wrongly. Does anyone have any suggestion on why the incandescent one works, while the LED one doesn't?

Since the LED's are diodes, do you think the guy who soldered the incandescent holder might have just not-cared about which was positive and which was negative and therefore gotten the negative and positive terminals switched?

Same issue, the incandescent on scooters has a live from the battery or 12v transformer to the earth pin and the switches swap the lower pins to earth. The dirty way to change this is swap the earth and main pins over on the headlight plug giving you normal lighting,but no full beam, other than that you need to rewrire the switch that may also cause problems to the rear light/brake light. Or a switching relay to swap poles.

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So what I did was measure the voltage at the connector that the incandescent holster plugs into. There are 3 wires there and I found 12V between two of them, so I fashioned an electrical connector from some thick wire I had and inserted it into the 2 appropriate holes in the connector that is running inside the scooter, apparently to the controller.

That worked, but I wasn't really bright enough, so I got a second LED light and mounted it in front of the dash. I wanted to connect it in parallel with the existing make-shift connector and this is where it started to get a bit messy as I didn't have everything I needed to make the connection. I tried wrapping the new LED's wires around the appropriate part of the thick wires that I had inserted into the connector. The second LED lit up too which was great, but I was in a bit of a rush and didn't secure the electrical connection very well.

Later that evening both LED's went out and when I measure the voltage at the connector at home, there was now no voltage across them. I suspect that during the ride, some of the wires must have short circuited and burned something out in the controller.

A little while later, my bike started behaving very strangely. It turns on with a key just like a normal scooter. However, my bike was turning on by itself even when the key wasn't inserted. When the bike was on, it would not respond to the throttle, but periodically jerk and stop, jerk and stop. When I tried to push the bike home, it was somehow applying something akin to a regenerative brake, even though my bike doesn't have regenerative braking. So it was basically impossible to push my bike anywhere (because of this magnetic braking effect) and it wasn't responding to the throttle. I was stuck for a while wondering what I should do.

I was lucky that I had taken off some of the plastic covering the insides of the bike, that I hadn't bothered to put back yet (as I'm still tinkering inside the bike), and I could just reach in and disconnect the battery. After doing that, I could push the bike. Then gingerly reconnecting my battery, I found that the bike's controller had reset to a sane state, akin to rebooting my computer (controller) and I could ride the bike home.

I was quite concerned about the bike after that and I went down and checked on it several times that evening and into the night with a volt meter. Luckily, it wasn't doing anything bad to my battery, but the burn-out of the connector for the lamp stayed dead. The rest of the bike seems to be functioning fine though after the reset.

Well, I learned that the light on my bike is connected to the controller and short-circuiting probably did something weird to my controller, putting it in a kind of unexpected state. Resetting the controller by disconnecting power seems to put it back into a sane state. Right now my plan is to run a wire from my battery through a separate switch to the lights taking the controller out of the control loop, and to use proper XT60 connectors instead.

So... I've now connected up the above LED to my battery through a switch. The battery is 60V nominal, but can be as high as 71V when freshly charged. The LED is rated from 9V to 80V.

I also have a Volt/ammeter connected on my bike and I can measure that this LED is drawing 1.7A or more than 100W! To me, that is a ridiculously high power draw for the LED. Does anyone know how these cheap LED's are able to operate over such a wide voltage range and why the power drawn is so much?

The LED has a pretty large heat sink, so I suspect there's just a simple resistor in there turning a lot of the current into heat... If anyone one has some insight on what's in there, would appreciate hearing your thoughts.

So... I've now connected up the above LED to my battery through a switch. The battery is 60V nominal, but can be as high as 71V when freshly charged. The LED is rated from 9V to 80V.

I also have a Volt/ammeter connected on my bike and I can measure that this LED is drawing 1.7A or more than 100W! To me, that is a ridiculously high power draw for the LED. Does anyone know how these cheap LED's are able to operate over such a wide voltage range and why the power drawn is so much?

The LED has a pretty large heat sink, so I suspect there's just a simple resistor in there turning a lot of the current into heat... If anyone one has some insight on what's in there, would appreciate hearing your thoughts.

Sounds like the LED is using a linear regulator to regulate current (a terrible way to do it.)

I'd recommend getting a better light, like one of the ebikes.ca lights. They use 1-4 watts and operate with an input up to 75 volts.